Assjgnos to ensign  carbijretor



o. H. ENSIGN Re. 18,767 2 Sheets-Sheet 1,

March 14, 1933, CARBURETOR Original Filed June 30, 1925 o. H. EVNSIGNGARBURETOR Re. 18,767 Original Filed Jun 50. 1925 Sheets-she 2 March 14,1933.

Inventor Orville .H'Ens rz Reissued Mar. 14, 1933 UNITED STATES PATENTOFFICE ORVILLE H. ENSIGN, or PASADENA, CALIFORNIA, Assrenoa TO ENSIGNcnnnunn ron co. LTD., on HUNTINGTON PARK, CALIFORNIA, A CORPORATION orCALIFORNIA CARBTUBETOR Original NOI; 1,792,080, dated February 10, 1931,Serial No. 40,532, filed June 30, 1925. Application fol reissue filedNovember 21,

This invention relates particularly to im-' provements in Venturi plaintube type carburetor and more particularly to improvements on the typeset forth in my copending application filed April 17, 1922, Serial No.554,027 which matured to Patent 1,721,618 granted July 23, 1929.

An object of this invention is to construct a novel carburetor whichwill successfully operate, both under load and idling, at on tremeangles from the normal vertical position without readjustment of themixture.

An object is to provide a novel and simple Venturi type carburetorhaving only one opening to the atmosphere. I

Another object is to provide novel means whereby the volume of fuelmaintained in the accelerating well during idling may be increased ordecreased by the changing of cal ibrated air bleeds.

Another object is to provide a carburetor of this type in which the airresistance in the air horn is reduced to a minimum, thus avoidingirregular proportioning characteristics which are imposed byobstructions usually found immediately below the Venturi throat.

A feature of this invention is that the idling mixture adjustment thatoperates on the load fuelorifice is so located with reference to thedepression at the venturi that a variable adjustment of the idlingmixture will not affect any load mixture.

Other objects, advantages and features of invention may appear from theaccompanying. drawings, the subjoined' detail description and theappended claims.

The accompanying drawings illustrate the invention in a form I atpresent deem most preferable.

Figure 1 is an axial sectional view of a carburetor constructed inaccordance with this invention with the'throttle slightly open for lightload and with the fuel at rest.

Fig. 1a is a fragmental' sectional view showing a modified form of theatomizing air and fuel passages.

Fig. 2 is an enlarged fragmental sectional view of the fuel dischargenozzle as included in the form shown in Fig. 1a.

1932. Serial No. 643,784.

F Fig. 3 is a section on irregular line 003m3,

Fig. 4 is a section on line m40c4, Fig. 1, showing the carburetor withthe float bowl and the bracket containing the main fuel adjustingelements removed.

Fig. 5 is a section on reduced scale on line 0c5w5, Fig. 1.

Fig. 6 is a fragmental section showing the sustained column of fuel inthe fuel passage during idling.

Y The carburetor is provided with an air intake 1, a suction passage 2controlled by a throttle 3, a constant level fuel chamber 4 suppliedwith fuel through the usual fuel connections 5 controlled by the valve6. A float 7 in the supply or fuel chamber 4 cooperates with the valve 6to maintain the fuel in said chamber at a constant level 8.

Fuel is delivered from the constant level fuel chamber to the suctionpassage through a fuel passage, which comprises a fuel riser 9 openinginto a suction chamber 11 through a fuel orifice 10, which may belocated at any suitable height in said riser, but is preferably locatednear the upper end thereof. The riser 9 is spaced from the walls of thesuction chamber 11 to provide ample clearance for fuel and air How. Thelower end of the suction chamber is extended in the form of a U-tubecomprising a horizontal passage 12, which opens through an inclinednozzle 13 to the main air stream slightly above the smallest diameter ofthe Venturi throat 13.

The major portion of the fuel passage is formed in a bracket ,member A,which is secured by screws 14 to the flanged face of the main bodymember B, which contains the air intake and suction passage. A member Cthat forms the constant level fuel chamber 4 is secured by screws 15 tothe member B and encloses the bracket member A when in position.

The air intake may be provided with the usual choke 16 which may beoperatedby any usual means connected to the shaft 17 The fuel chamber 4is supplied with air through a balancing air passage that com prises apassage 18 formed in member A that connects to a cored passage 19 formedin the member B from which a balance tube 20 leads into the air intake,thus providing air in the float chamber coordinating with the airpressure in the air intake.

The suction passage is provided at its lower end with a member 21 whichis shaped to form a Venturi throat of the usual form. A screw 22extending through the wall of the member B secures the member 21 in thesuction passage. 8

The nozzle 13 is provided with a threaded portion 23 that is threadedinto the member B and isalso provided with a contracted extension 24that is received in and extends through a calibrated clearance bore 25formed in and extending th ough one wall of the Venturi member 21, whichforms the Venturi throat. The bore 25 at the inner 38- riphery of theVenturi member forms a definite clearance around the extension 24 of thenozzle 13 and is enlarged at the outer periphery of member 21 as at 25to form ample clearance to permit flow of fuel therethrough as will bemore fully hereinafter explained.

In all the forms shown the nozzle 13 is provided with a bore enlarged atits entrance, that is to say at the end into which the fuel enters saidnozzle from the suction chamber, as more particularly shown in Figs. 2and 6.

In the form shown in Figs. 1a and 2 the horizontal passage 12 of thefuel passage is of slightly smaller diameter than in the form shown inFig. 1 and the end thereof adja cent the nozzle 13 is enlarged to formenlargement 50 in the bottom of the U-tube fuel passage. The purpose ofthis enlargement V will be more fully hereinafter set forth.

An idling by-pass 26 opens through an idling fuel jet 27 to the suctionpassage beyond the throttle and is continued by the cored passage 28,which is curved at 29 to clear the nozzle 13, and is extended by anidling by-pass tube 30 to a sump 31 in the air intake. The lower end oftube 30 is provided with cross holes 32 to insure full opening of thetube 30 at its lower end. 7

The idling by-pass is connected to the enlargement 25 of bore 25 by adrilled hole 33. The idling by-pass 26 is provided with a valved vent 34that opens into the main air stream at a point slightly below thesmallest portion of the Venturi throat and is controlled by a suitableneedle valve 35, which is held in adjusted position by a spring retainer36.

The idling by-pass is provided with an additional air bleed, which opensinto the cor-ed passage 19 of the balancing means through the calibratedplug or vent 37.

The vent .37, the clearance bore 25, the bypass tube 30, constitutefixed vents to reduce the pressure in the idling by-pass 26 from thatabove the throttle. The vent 34 provides a suitable additional ventwhich is used to adjust the depression in the idling bypass. Thisdepression is applied to the suction chamber 11, and thus to the fuelorifice 10, by means of the calibrated idling depression passage 38 theflow through which may be varied by changing the calibrated plug 38.From the foregoing it is apparent that it is possible to adjust the idlemixture by means of the valve 35.

Air is admitted from the float chamber to the suction chamber throughthe calibrated vent 39, and thereby provides means connecting thesuction chamber to the air intake through the balancing air passage.

Small holes 40 are provided in the nozzle 13 and such holes connect thebore of the nozzle 13 to the enlarged clearance 25', and thus by thehole 33 to the idling by-pass and thus to the idling fuel jet 27 hehorizontal passage 12 of the fuel passage is connected to the passage 38by means of a supplemental passage 41, which is preferably restricted atits upper end. This passage provides additional accelerating fuel andadmits air from the upper end of the suction chamber to the fuel passagenear the nozzle 13, thus aiding in early delivery of accelerating fuel.

The member B is provided with a flanged face 42 in which a major portionof the idling by-pass 26 is formed by coring the member when the same iscast.

A common gasket 43 is interposed between the members B, A and C toprovide an air and gasoline tight joint between such parts.

A packing 44 interposed betweenthe top of member A and member C providesa tight joint between said members around the opening 45 through whichextends the boss 46 of member A and in which boss is threaded the highspeedadjusting needle 47 that adjusts the opening of the fuel orifice10.

The member A is provided with a bore forming the suction chamber andsuch bore is threaded at the lower end to receive the threaded portion48 of the riser 9, and thus provides simple means for assembling thefuel riser.

The air intake in this application is understood to include that portionof the main air stream from the beginning of the air intake to the lowerend of the venturi, and the suction passage includes that portion of themain air stream from the lower end of the venturi to the carburetorflange y and such portion may include what has heretofore beendesignated in some types of carburetors as a mixing chamber, a mixtureoutlet and a suction passage.

An annular groove 49 formed in the wall of the air intake preventscondensed fuel fromrunning down the walls of the air intake past thechoke valve 16.

The end of tube 30 extends into the lower end of this groove 49, whichlower end forms the sump and the accumulated condensed fuel is deliveredfrom the sum to beyond the throttle through the idling y-pass and anyfuel fallin down from the suction passage as the engine slowly stops iscarried into the engine through the tube 30 and idling bypass and thusprevents dripping of fuel from the carburetor after the engine hasstopped.

The construction shown in Fig. 1 is satisfactory for all heavy dutymotors with relatively large displacement and moderate speeds.

The construction of the fuel passage and supplemental passage 41', shownin Figs. 1a and 2, is deemed preferable for such types of motors thatdevelop a large amount of power from a relatively small displacement andat relatively high motor speeds.

Due to the small displacement of these high speed motors when idlingthey require very little fuel for idling and it has been found diflicultto form a seal in the lower portion of the U-tube fuel. passage, whensuch fuel passage is large enough to develop full power as with thedevice in Fig. 1; and in such high speed motors I prefer to use theconstruction shown in Fig. 1a and in which the supplemental passage llis open to the passage 38 its full diameter as shown in Fig. 1a.

This passage 41 being open full size to the passage 38, without therestriction at the top, as shown in Fig. 1, allows the passage of moreair from the calibrated vent 39 through passage 41' under load",,wh-ichagain makes possible the reduction in diameter of the horizontal portion1 2' of the fuel assage so that this portion 12 is just su cientIylargeenough for the How of fuel and some small amount of air.

The lower end of the. passage 41 is extended tobelow the center of theportion 12' of the fuel passage by a tube 51, thusmalring it possible toreadily seal the fuel passage, when idling.

In operation of the device shown in Fig. 1, fuel is supplied to. theconstant level fuel chamber 4 in the, usual way. When the carburetor isat, rest this fuel is protected from overflow into the suction chamberby the proper height of." the top of the fuel riser 9 above the constantfuel level 8.

When under load with. the throttle valve at any degree of opening aboveidling the normal flow of fuel is through. the bore ofthe riser 9,,thencethrough the restricted fuel orifice 10-u-nder control; ofthe highspeed adj usting needle 7 into the U-tube fuel passage comprising thesuction chamber 11, intothe lower end of which. the-riser 9; extends andforms an annulus between" the riser and the walls of the suctionchamberthatforms one limb of the U-tube,thence into: the horizontalpassage 12 and upwardly inclined nozzle 1 3 from Which-thefuelisdischarged intothe main air stream at the Venturi throat slightlyabove the smallest diameter of the Venturi throat.

At the same time air will be drawn into the fuel passage through thecalibrated vent 39 and flow with the fuel through the fuel passage,following two paths, one down through the annulus about the riser; andthe other by way of the supplemental passage 4-1 which is contracted atthe top, thus supplying air for atomization and rapid beginning ofdelivery of fuel through the fuel nozzle 13-.

When idling the throttle is closed and the depression in the chamber 11is increased over that applied in such chamber 11 through the nozzle 13.This increased depression is applied to the suction chamber through theidling fuel jet 27 and the idling by-pass 26 and the calibrated idlingdepression passage 38 that opens from the idling bypass 26 into thesuction chamber above the riser. This increased depression from abovethe throttle is modified by fixed bleeds and by the valved vent 34.

The idling by-pass tube 30 constitutesone of these fixed bleeds and suchbleed 30 performs the additional function of conducting liquid fuel fromthe sump 31 to the idling by-pass. The definite clearance around thedischarge end of the nozzle 13 connected to the idling by-passthroughthe drill hole 33 constitutes a second fixed bleed and the cal-ibra'ted plug 37, a third fixed bleed.

The first thus reduces the depression in the idling by-pass 26 adefinite amount below that from above the throttle and the valved vent34 under control of the needle valve 35 is used to control or vary thereduction of the depression in the idling by-pass by'supp'lementing theconstant or fixed bleeds by a variable bleed.

If the throttle is closed to idling position after the engine has-beenrunning at, anyload or speed condition, the fuel moving through the fuelpassage becomes temporarily at rest in the horizontal portion 12 of thefuel pass sage and seals off the connection betwen such horizontalportion and the annulus formed around the riser in the suction chamber-By thus sealing the passage 12 the depression applied in the suctionchamber 11 through the idling byJ-pass. will immediately rise in valuein excess of the depression at the end of the nozzle 13 in the venturiand such excess in depression will sustain inthe suction chamber and inthe supplemental passage 41 against the force of gravity, a column offuel the level of which is considerably higher than the discharge end ofthe nozzle 13. and the height of this sustained column of fuel iscontrolliedrby opening or closing the valved vent The fuel accumulatedin. the supplemental passage 41 is sustained. atthe-sameor a great.-

er height than the fuel inithe suction chamber and provides additionalfuel-for acceleration purposes.

Continued operation of the engine causes fuel to be lifted over the topof the riser from which it will be added to the sustained column of fuelin the suction passage and this addition of fuel will cause an equalamount of fuel to be displaced from the end of thenozzle 13 or throughthe small holes 40 provided-in the nozzle 13. The fueldischarged fromthe end of thenozzle 13 during-idling will flow ,in a small film aroundthe edge of the nozzle 13 and thence into the enlargement 25 331; theinner end of the bore 25 from whichit will be drawn intothe idlingby-pass, through the drill hole 33 and thence to beyond the throttlewhere it is, delivered to the suction passage'through the idling fueljet 27. If for any reason the fuel emitted-from the discharge end of thenozzle 13 during idling should flow down the side walls of the airintake, it will be stopped from flowing out of the air intake bythe-annular grove 49 from which it will be de livered to the idlingby-pass through tube 30.

Upon opening the throttle fuel immediately begins to discharge morerapidly from the nozzle 13 because the depression sustaining the columnof fuel in thesuction chamber and thesupplementalpassage has beenremoved, and such discharge of fuel is followed by air from the airintake through the vent 39 and then, first through the supplementalpassage 41 and second through the annulus in the suction chamber. Theflow of air through the supplemental passage all begins at-omizing thefuel at an early period in the discharge from the nozzle and as theengine gains speed the flow of air through the passage 41 and theannulus will gradually clean out all of the sustained fuel untiltheengine reaches a speed that will require all of the passage 12 forthe newly proportioned fuel and air under any particular continuous loadoperation so that under any considerable load no fuel will remain in thefuel passage other than that continuously supplied for operation of theengine. r i

The openings 40 upon losing the throttle to idling position facilitateimmediatelyenriching the idling mixture by drawing directly upon thefuel through the idling lay-- pass until thefuel reaches the openings10.

The size of the openings 40 may be such that when idling substantiallyall of the fuel required to supply the engine will flow through suchopenings but some of the fuel mayfiow past'the openings 40 and dischargefrom the end of the fuel nozzle 13 and be delivered to the engine asabove set forth.

The air supplied to the constant level fuel chamber 4 and to the suctionchamber and fuel passage provides a balancing means to maintain apressure in the fuel chamber. co-

ture.

ordinating with that in the air intake and is similar in many respectsto the balancing system set forth in my Patent No. 1,506,229, patentedAugust 26, 192%. v vThe function of the various fixed bleeds forthe'idling by-pass is believed to be apparent to'anyoneversed in the artand therefore only a brief explanation of the same will be given. Thecalibrated vent 39 has to do with the effectiveness of atomization andrapid delivery of the fuel sustained during idling for accelerationpurposes. Enlarging the vent 39 increases the fuel economy and reducesthe amount of fuel sustained for acceleration purposes. a

Theidlingdepression passage 38 has to do with developing the correctidling mix- The bleed 37 has to do, with refining the development of theidling depression changingthe size of the passage 38. One drill size,may make too great a change in the idling mixture and leave the idlingmixture beyond the control of the valved vent 34;. Then, in erder tobring the idling mixture under the control of the valved vent thecalibrated plug or vent 37 can be changed to a larger or smaller size,as the case may be. This function is the main reason for the vent 37.

However, the vent 37 combined with the passage 38 performs anotherfunction. En-

larging the vent 37, all other things being constant, increases thedepression applied on the surface of the fuel in the fuel supply chamber4 during idling. Such depression is operatively effective on the fuelsupply to the orifice 10 to bring about the same condition as though thefuel level in the chamber 4 had been lowered and when such depressionoccurs the depression applied in the suction chamber 11 must beincreased to draw the fuel over the top of the riser 9, and when thedepression in chamber '11 is increased the height ofthe sustained columnof fuel is greater whenever the vent 37 is enlarged.

When a good metering curve and good idling mixture is obtained, but thepick-up from idling is not quite satisfactory, enlarging the passage 38and then enlarging the vent 37 to again bring the idling mixture withinthe control of the valved vent 34 will increase the height ofthe columnof fuel sustained in the fuel and supplemental passages and thus providethe desired fuel for acceleration from idling speed without requiringany change in the dimensions of the parts containing such acceleratingfuel.

' The height of the fuel sustained in the auxiliary passage 41 isdetermined by the velocity head through'the vent 39 and the passage 38The higher the velocity the higher the column of fuel.

The operation of the device shown in Figs. 1a and 2 is practically thesame as above set forth with respect to the operation of the deviceshown in Fig. 1 except that upon closing the throttle after load toidling position, fuel will immediately accumulate in the enlargement 50of the fuel passage and will be drawn with air through the supplementalpassage 4-1 and the calibrated plug 38 and thereby supplies the motorwith the necessary fuel until suiiicient fuel has accumulated in theannulus around the riser and the horizontal portion 12 of the fuelpassage to seal ofl" the lower end of this tube 51. lVhen such sealtakes place the fuel will rise in the passage 41 and be sustainedtherein against the force of gravity and form an accumulation of fuelwhich serves as accelerating fuel. When the fuel seals the portion 12and the passage ll, immediately thereafter the full idle mixture isobtained and the fuel will flow through the nozzle 13 and be deliveredin the normal way to the main air stream.

Upon suddenly opening the throttle due to the fact that the lower end ofthe tube 51 is nearest the nozzle, this portion of the accelerating fuelis discharged quickest and is followed immediately by air from the vent39 through idling depression passage 38 and thus produces earlyatomization of fuel in the accelerating period.

The remainder of the fuel accumulated in the fuel passage is slowlydelivered to the main air stream and continues to supply acceleratingfuel for a smooth aggressive acceleration which is highly desired onmotors Which obtain their maximum horse power at high motor speed withrather small displacement.

I claim:

1. A carburetor comprising an air intake; a throttle controlled suctionpassage; a constant level fuel chamber; a fuel passage com prising asuction chamber, a fuel riser opening from said fuel chamber into saidsuction chamber above the normal fuel level; and a U-tube portionconnecting said suction cham her to said suction passage; an idlingby-pass leading from near the delivery end of the fuel passage to thesuction passage above the throttle; and calibrated means supplying airto said suction chamber.

2. A carburetor comprising an air intake; a throttle controlled suctionpassage; a constant level fuel chamber; an idling by-pass leading fromnear the delivery end of the fuel passage to the suction passage abovethe throttle; a fuel passage comprising a suction chamber; a fuel riseropening from said fuel chamber into said suction chamber above thenormal fuel level, and a U-tube portion connecting said suction chamberto said suction passage; a passage connecting said suction chamber andsaid idling bypass; calibrated means supplying air from said air intaketo said suction chamber; and a valve controlled passage open from thesuction passage slightly below the Venturi throat to said idling by-passto control the depression in the suction chamber when idling.

8. A carburetor comprising an air intake; a throttle controlled suctionpassage; a constant level fuel chamber; an idling by-pass; a fuelpassage comprising a suction chamber, fuel riser opening from said fuelchamber into said suction chamber above the normal fuel level, and aU-tube portion connecting said suction chamb r to said suction passage;a connecting said suction chamber above the normal fuel level to saididling lay-pass; means connected to said air intake for sup lying tosaid fuel chamber; and means connecting said idling by-pass with saidfuel chamber above the normal fuel level therein.

4. In a carburetor, an air intake, a throttle controlled suctionpassage, a fuel passage connected to deliver fuel from a fuel supply tosaid suction passage and comprising a suction chamber, a fuel riserextending into said suction chamber above the normal fuel level andadapted to deliver fuel by overflow into said suction chamber above thenormalfuel level, said suction chamber being connected below theconstant fuel level to the suction passage by a suitable nozzle; anidling bypass connected near the delivery end of said fuel passage andconnected to apply in said suction chamber a depression from beyond thethrottle to furnish fuel during idling;.and means connecting said airintake with the fuel supply chamber and with said suction chamber.

5. A carburetor comprising a Venturi throat; an air intake, and athrottlecontrolled suction passage; a suction chamber; means adapted todeliver fuel to said suction chamher; a fuel passage adapted to deliverfuel irom said suction chamber to said suction passage; a constantlevelfuel chamber supplied with air from the air intake and connected to saidmeans to supply fuel to said suction chamber; an idling by-passconnected to the suction passage above the throttle and also connectedto the suction chamber through a calibrated passage; said idling bypassbeing open through a calibrated plug to the passage connecting the airintake and the fuel supply chamber; an adjustable vent connecting theidling by-pass and the suction passage at a point below the smallestdiameter of the Venturi throat; said fuel passage being adapted andarranged to accumulate fuel against the force of gravity under theadjusted depression in the idling by-pass for purpose of supplying theidling mixture and for acceleration.

6. A carburetor having a Venturi throat and comprising an air intake; athrottle controlled suction passage; a constant level fuel chamber; afuel passage in the form of a Ell-tube adapted to deliver fuel from saidfuel chamber to said suction passage; there being an enlargement in thelower portion of the U-tube passage; anidling by-pass open from beyondthe throttle; a passage connecting said idling by-pass intermediate itsends to said suction chamber above the normal fuel level in said fuelchamber; and a supplemental passage connecting the fuel passage belowthe center of said enlargement to the passage that connects the idlingby-pass to the fuel chamber.

7 In a carburetor, an air intake; a throttle controlled suction passage;a fuel passage connected to deliver fuel from a fuel supply to saidsuction passage and comprising a suction chamber, a fuel riser extendingto said suction chamber above the normal fuel level and adapted todeliver fuel into said suction chamber above the normal fuel level, saidsuction chamber being connected below the constant fuel level to thesuction passage by a suitable nozzle; an idling by-pass connected nearthe delivery end of said fuel passage to apply in said suction chamber,a depression from beyond the throttle to furnish fuel during idling.

8. A carburetor comprising an air intake; a throttle controlled suctionpassage; a constant level fuel chamber; a fuel passage comprising asuction chamber, a fuel riser opening from said fuel chamber to saidsuction pass connected near the delivery end of said fuel passage andconnected to apply in said suction chamber a depression from beyond thethrottle tov furnish fuel during idling; and means connecting said fuelsupply chamber and said suction chamber with the atmosphere.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 3rd day of November, 1932.

' ORVILLE- H. ENSIGN.

chamber above the normal fuel level; and a passage connectingsaidsuction chamber to said suction passage; an idling by-pass leading fromnear the delivery endof the fuel passage to the suction passage abovethe throttle; and calibrated means supplying air to said suctionchamber.

9. A carburetor comprising an air intake; a throttle controlled suctionpassage; a constant level fuel chamber; a fuel passage comprisingasuction chamber; an idling by-pass leading from near therdelivery end ofthe fuel passage to the suction passage above the throttle; a fuel riseropening from said fuel chamber to said suction chamber above the normalfuel level, and a passage connecting said suction chamber to saidsuction passage; a passage connecting said suction chamber and saididling by-pass; calibrated means supplying air from said air intake tosaid suction chamber; and a valve controlled passage open from thesuction passage to said idling by-pass to control the depression in thesuction chamber when idling.

10. In a carburetor, an air intake, a throttle controlled suctionpassage, a fuel passage connected to deliver fuel from a fuel supply tosaid suction passage and comprising a suction chamber, a fuel riserextending into said suction chamber above the normal fuel level andadapted to deliver fuel by overflow into said suction chamber above thenormal fuel level, said suction chamber being connected below theconstant fuel level to the suction passage by a suitable nozzle; anidling by-

